Organic light emitting display and manufacturing method thereof

ABSTRACT

An organic light emitting display including a substrate, a first electrode and a second electrode on the substrate and facing each other, at least two organic light emitting layers between the first electrode and the second electrode, and at least two color filters on the second electrode, the organic light emitting layers emitting a first color light, and the color filters emitting a second color light and a third color light.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation application of application Ser. No. 16/547,776,filed Aug. 22, 2019, which is a continuation of application Ser. No.16/163,839, filed Oct. 18, 2018, now U.S. Pat. No. 10,403,688, issuedSep. 3, 2019, which in turn is a continuation of application Ser. No.15/661,409, filed Jul. 27, 2017, now U.S. Pat. No. 10,109,685, issuedOct. 23, 2018, which in turn is a continuation of application Ser. No.14/712,190, filed May 14, 2015, now U.S. Pat. No. 9,722,001, issued Aug.1, 2017, the entire contents of all being hereby incorporated byreference.

Korean Patent Application No. 10-2014-0175994, filed on Dec. 9, 2014, inthe Korean Intellectual Property Office, and entitled: “Organic LightEmitting Display and Manufacturing Method Thereof,” is incorporated byreference herein in its entirety.

BACKGROUND 1. Field

Provided are an organic light emitting display and a manufacturingmethod thereof.

2. Description of the Related Art

An organic light emitting display may be used in a small mobile devicesuch as a smart phone in addition to being applied to a large-sized TVwith a large screen.

SUMMARY

Embodiments may be realized by providing an organic light emittingdisplay, including a substrate; a first electrode and a second electrodeabove the substrate and facing each other; at least two organic lightemitting layers between the first electrode and the second electrode;and at least two color filters on the second electrode, the organiclight emitting layers emitting a first color light, and the colorfilters emitting a second color light and a third color light.

The first color light may be blue light.

The color filters may include a quantum dot material.

The color filters may include a first color filter and a second colorfilter, and the first color filter may emit the second color light, andthe second color filter may emit the third color light.

The second color light may be green light and the third color light maybe red light.

Each of the color filters may include a first region adjacent to thesecond electrode and a second region, and the quantum dot material maybe in the second region.

The organic light emitting display may further include a chargegenerating layer between the at least two organic light emitting layers.

The charge generating layer may include an n-type charge generatinglayer and a p-type charge generating layer.

The n-type charge generating layer may be adjacent to the firstelectrode, and the p-type charge generating layer may be adjacent to thesecond electrode.

The first electrode may be an anode, and the second electrode may be acathode.

The organic light emitting layers may include a soluble material.

The organic light emitting display may further include an n-type chargegenerating layer between the second electrode and the light emittinglayers.

The organic light emitting display may further include a buffer layerbetween the second electrode and the light emitting layers. The bufferlayer may include one or more of WO₃, MoO_(x), orhexaazatriphenylenehexacarbonitrile (HATCN).

The organic light emitting display may further include a sealingsubstrate sealing the organic light emitting display. The color filtersmay be between the sealing substrate and the second electrode.

The sealing substrate may include a transparent material, and lightemitted from the organic light emitting layers may be emitted throughthe sealing substrate.

Embodiments may be realized by providing a manufacturing method of anorganic light emitting display, including forming a first electrodeabove a substrate; forming at least two organic light emitting layersabove the first electrode with a charge generating layer between theorganic light emitting layers; and forming a second electrode above theat least two organic light emitting layers, the organic light emittinglayers being formed using a soluble material.

The manufacturing method may further include one or more of forming oneor more of a hole injection layer or a hole transport layer between thefirst electrode and the organic light emitting layers to supply holesgenerated from the first electrode to the organic light emitting layers;or forming one or more of an electron injection layer or an electrontransport layer between the second electrode and the organic lightemitting layers to supply electrons generated from the second electrodeto the organic light emitting layers.

The organic light emitting layers may be formed under conditions ofnormal pressure.

The manufacturing method may further include forming a buffer layerincluding one or more of WO₃, MoO_(x), or1,4,5,8,9,11-hexaazatriphenylenehexacarbonitrile (HATCN) below thesecond electrode.

The manufacturing method may further include preparing a sealingsubstrate on which at least two color filters including a quantum dotmaterial are formed; and laminating the substrate and the sealingsubstrate with the at least two color filters facing the secondelectrode.

BRIEF DESCRIPTION OF THE DRAWINGS

Features will become apparent to those of skill in the art by describingin detail exemplary embodiments with reference to the attached drawingsin which:

FIG. 1 illustrates a schematic cross-sectional view of an organic lightemitting display according to an embodiment;

FIG. 2 illustrates a schematic cross-sectional view of an organic lightemitting display according to an embodiment;

FIG. 3 illustrates a schematic cross-sectional view of an organic lightemitting display according to an embodiment;

FIG. 4 illustrates a schematic cross-sectional view of an organic lightemitting display according to an embodiment;

FIG. 5 illustrates a schematic cross-sectional view of an organic lightemitting display according to an embodiment; and

FIG. 6 illustrates a schematic cross-sectional view of an organic lightemitting display according to an embodiment.

DETAILED DESCRIPTION

Example embodiments will now be described more fully hereinafter withreference to the accompanying drawings; however, they may be embodied indifferent forms and should not be construed as limited to theembodiments set forth herein. Rather, these embodiments are provided sothat this disclosure will be thorough and complete, and will fullyconvey exemplary implementations to those skilled in the art.

In the drawing figures, the dimensions of layers and regions may beexaggerated for clarity of illustration. It will also be understood thatwhen a layer or element is referred to as being “on” another layer orsubstrate, it can be directly on the other layer or substrate, orintervening layers may also be present. Further, it will be understoodthat when a layer is referred to as being “under” another layer, it canbe directly under, and one or more intervening layers may also bepresent. In addition, it will also be understood that when a layer isreferred to as being “between” two layers, it can be the only layerbetween the two layers, or one or more intervening layers may also bepresent. Like reference numerals refer to like elements throughout.

Although the terms “first, second, and so forth” are used to describediverse constituent elements, such constituent elements are not limitedby the terms. The terms are used only to discriminate a constituentelement from another constituent element. Accordingly, in the followingdescription, a first constituent element may be a second constituentelement.

Hereinafter, embodiments will be described with reference to theaccompanying drawings.

FIG. 1 illustrates a cross-sectional view of an organic light emittingdisplay according to an embodiment.

Referring to FIG. 1, an organic light emitting display according to anembodiment may include a substrate 50, a first electrode 100 and asecond electrode 200 disposed above the substrate 50 to face, e.g., beseparated from, each other, at least two organic light emitting layers300 and 400 located between the first electrode 100 and the secondelectrode 200, and at least two color filters 900 located on the secondelectrode 200. The organic light emitting layers 300 and 400 may emit afirst color light L1, and the color filters 900 may emit a second colorlight L2 and a third color light L3, respectively.

The substrate 50 may include an insulating substrate. If the organiclight emitting display is a front emission type display, asemi-transparent or non-transparent substrate may be used as theinsulating substrate.

The insulating substrate may be made of a material such as glass,quartz, and polymeric resin. Examples of the polymer material mayinclude polyethersulphone (PES), polyacrylate (PA), polyarylate (PAR),polyetherimide (PEI), polyethylene napthalate (PEN), polyethyleneterepthalate (PET), polyphenylene sulfide (PPS), polyallylate, polyimide(PI), polycarbonate (PC), cellulose triacetate (CAT or TAC), celluloseacetate propionate (CAP) and a combination thereof. In some embodiments,the insulating substrate may be a flexible substrate made of a flexiblematerial such as polyimide (PI).

Although not shown, the substrate 50 may further include otherstructures disposed on the insulating substrate. Examples of the otherstructures may include a wiring, an electrode, and an insulating film.In some embodiments, the substrate 50 may include a plurality of thinfilm transistors arranged on an insulating substrate. The drainelectrodes of some of the thin film transistors may be connectedelectrically to the first electrode 100. The thin film transistor mayinclude an active region made of, for example, amorphous silicon,polycrystalline silicon, or single crystalline silicon. In embodiments,the thin film transistor may include an active region containing anoxide semiconductor.

The first electrode 100 may be disposed on the substrate 50, and thefirst electrode 100 may be disposed in each pixel of the organic lightemitting display. The first electrode 100 may be an anode, and the firstelectrode 100 may include a conductive material that may have arelatively large work function compared to the second electrode 200. Forexample, the first electrode 100 may include Indium-Tin-Oxide (ITO),Indium-Zinc-Oxide (IZO), Zinc Oxide (ZnO), or Indium Oxide (In₂O₃). Theabove-mentioned conductive materials may have a transparent property aswell as a relatively large work function.

In addition to the above-mentioned conductive materials, a reflectivematerial such as silver (Ag), magnesium (Mg), aluminum (Al), platinum(Pt), lead (Pd), gold (Au), nickel (Ni), neodymium (Nd), iridium (Ir),chromium (Cr), lithium (Li), calcium (Ca) or a mixture thereof may befurther included in the first electrode 100. The first electrode 100 mayhave a single layer structure formed of the above-mentioned conductivematerial and reflective material, or may have a multilayer structureformed by stacking plural layers. For example, the first electrode 100may have a multilayer structure of ITO/Mg, ITO/MgF, ITO/Ag, orITO/Ag/ITO.

The second electrode 200 may be a cathode, and may be a front electrodeor common electrode formed regardless of pixels. The second electrode200 may include a conductive material that may have a relatively lowwork function compared to the first electrode 100.

The second electrode 200 may include Li, Ca, LiF/Ca, LiF/Al, Al, Mg, Ag,Pt, Pd, Ni, Au Nd, Ir, Cr, BaF, Ba, or a compound or mixture thereof(e.g., a mixture of Ag and Mg). The second electrode 200 may furtherinclude an auxiliary electrode. The auxiliary electrode may furtherinclude a film formed by depositing the material, and transparent metaloxide, formed on the film, for example, Indium-Tin-Oxide (ITO),Indium-Zinc-Oxide (IZO), Zinc Oxide (ZnO), Indium-Tin-Zinc-Oxide, orMnO₂.

As the second electrode 200, a conductive layer that may have a smallwork function may be formed as a thin film, and a transparent conductivefilm, for example, an Indium-Tin-Oxide (ITO) layer, an Indium-Zinc-Oxide(IZO) layer, a Zinc Oxide (ZnO) layer, or an Indium Oxide (In₂O₃) layer,may be stacked thereon.

As described above, the second electrode 200 may be formed of atransparent conductive material, the light generated from the organiclight emitting layers 300 and 400 may be emitted forward through thesecond electrode 200, and it may be possible to implement a frontemission type organic light emitting display.

The first color light L1 may be blue light. For example, the organiclight emitting layers 300 and 400 emitting the first color light L1 maybe blue organic light emitting layers. The organic light emitting layers300 and 400 may include a soluble material, and in a manufacturingprocess of an organic light emitting display, which will be describedlater, the organic light emitting layers may be formed by an ink-jetprinting method or a discharging method using a slit nozzle withoutusing a deposition method. In the case of the deposition method, theunit price of the product may be increased, for example, due to anexpensive deposition apparatus. In the case of forming the organic lightemitting layers by using a soluble material, an inexpensive apparatusmay be used, and it may be possible to reduce the unit price of theproduct.

By forming at least two organic light emitting layers 300 and 400, itmay be possible to emit a large amount of light. For example, as shownin FIG. 1, the organic light emitting layers 300 and 400 may include afirst organic light emitting layer 300 and a second organic lightemitting layer 400. Blue light may be emitted from the first organiclight emitting layer 300 and the second organic light emitting layer400, and it may be possible to increase the luminous efficiency of theorganic light emitting display by increasing the amount of lightemitted. Illustrated is an embodiment including organic light emittinglayers, i.e., the organic light emitting layers 300 and 400. If a largeramount of light emitted is required, another organic light emittinglayer, e.g., a third organic light emitting layer (not shown) or afourth organic light emitting layer (not shown), may be added, and theselayers may be organic light emitting layers that emit blue light.

Holes may be provided from the first electrode 100 and electrons may beprovided from the second electrode 200, the provided holes and electronsmay be coupled with each other in the organic light emitting layers 300and 400 located between the first electrode 100 and the second electrode200, and light may be generated by the energy generated when exitonsformed by the coupling fall to the ground state.

The color filters 900 may allow the light provided from the organiclight emitting layers 300 and 400 to be emitted as the second colorlight L2 or the third color light L3. For example, the color filters 900may convert the first color light L1 provided from the organic lightemitting layers 300 and 400 into the second color light L2 or the thirdcolor light L3.

The color filters 900 may include a first color filter 910 and a secondcolor filter 950. The first color filter 910 may emit the second colorlight L2, and the second color filter 950 may emit the third color lightL3. The second color light L2 may be green light and the third colorlight L3 may be red light. The color filters 910 and 950 may be formedonly in some regions of the upper side of the organic light emittinglayers 300 and 400, and may not be formed in some regions of the upperside thereof. For example, as shown in FIG. 1, the first color filter910 and the second color filter 950 may be formed at some positionsabove the organic light emitting layers 300 and 400, and the colorfilters may not be formed at some positions above the organic lightemitting layers 300 and 400. The first color light L1 that may be bluelight may be emitted directly at the position at which the color filteris not formed, and the blue light passing through the first color filter910 may be converted into the second color light L2 and emitted as greenlight. The blue light passing through the second color filter 950 may beconverted into the third color light L3 and emitted as red light.

The organic light emitting display may include a sealing substrate 700,and the sealing substrate 700 may seal (cap) the organic light emittingdisplay while preventing various organic layers constituting the organiclight emitting display from being damaged by being exposed to theoutside. The sealing substrate 700 may be formed of a transparentmaterial, and the light emitted from the organic light emitting layers300 and 400 may be emitted through the sealing substrate 700. Asdescribed above, the sealing substrate 700 and the second electrode 200may be formed of a transparent material, and light may be freely emittedthrough the front surface of the organic light emitting display.

The above-described color filters 900 may be formed on, for example, thesealing substrate 700, and the color filters 900 may be formed directlyon the second electrode 200.

The color filters 900 may include quantum dot materials 10 and 20.Quantum dots refer to semiconductor nanoparticles that may have a sizeof several nm to several tens nm, and may have characteristics thatemission light varies depending on the size of the particles by aquantum confinement effect. For example, the quantum dots may generatestrong light in a narrow wavelength band, and light emitted from thequantum dots may be generated when the electrons in an unstable(excited) state fall from a conduction band to a valence band. Thequantum dots may have a property that generates light having a shortwavelength as the particles are smaller, and generates light having along wavelength as the particles are larger. By adjusting the size ofthe quantum dots, it may be possible to generate light having a desiredwavelength in a visible light region. Therefore, it may be possible toobtain light of a desired wavelength by adjusting the size of thequantum dot materials 10 and 20.

The quantum dot materials 10 and 20 may have a particle size of 10 nm orless. For example, the quantum dot materials may emit red light if theparticle size ranges from 55 to 65 Å, may emit green light if theparticle size ranges from 40 to 50 Å, and may emit blue light if theparticle size ranges from 20 to 35 Å. The quantum dot materials may emityellow light if the particle size is intermediate between those of thequantum dot material emitting red light and the quantum dot materialemitting green light. By including the quantum dot materials in thecolor filters 900, it may be possible to increase the color purity.

The quantum dot materials 10 and 20 may include silicon (Si)-based nanocrystals, Group II-VI-based compound semiconductor nano crystals, GroupIII-V-based compound semiconductor nano crystals, Group IV-VI-basedcompound semiconductor nano crystals, and mixtures thereof.

The Group II-VI-based compound semiconductor nano crystals may be formedof one selected from CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, HgS, HgSe, HgTe,CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS,CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HggZnTe, CdZnSeS,CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe andHgZnSTe.

The Group III-V-based compound semiconductor nano crystals may be formedof one selected from GaPAs, AlNP, AINAs, AlPAs, InNP, InNAs, InPAs,GaAlNP, GaAlNAs, GaAlPAs, GaInNP, GaInNAs, GaInPAs, InAlNP, InAlNAs, andInAlPAs.

The Group IV-VI-based compound semiconductor nano crystals may be formedof SbTe.

Each of the color filters 900 may emit desired light, but may emit lighthaving higher purity if the quantum dot materials 10 and 20 are includedin the color filters 900 as described above. For example, in the case ofthe color filters 900 including the first color filter 910 and thesecond color filter 950, if the first color filter 910 emits green lightand the second color filter 950 emits red light, the first color filter910 may include the quantum dot material 10 corresponding to thewavelength range of 500 nm to 570 nm, which is a green light wavelengthrange. The second color filter 950 may include the quantum dot material20 corresponding to the wavelength range of 600 nm to 670 nm, which is ared light wavelength range.

Although not separately shown, an n-type charge generating layer may befurther included between the second electrode 200 and the light emittinglayers 300 and 400 to impart the conductivity between the secondelectrode 200 and the light emitting layers 300 and 400.

A buffer layer 600 may be further included between the second electrode200 and the light emitting layers 300 and 400. For example, the bufferlayer 600 may include one or more of WO₃, MoO_(x), orhexaazatriphenylenehexacarbonitrile (HATCN). The second electrode 200may be formed by a deposition method or a sputtering method by using amaterial such as an inorganic material. Various kinds of organic layerslocated therebelow may be damaged, or their functions may bedeteriorated. By forming the buffer layer 600, it may be possible toprevent the deterioration of the functions by the second electrode. Ifthe n-type charge generating layer is further included, the buffer layer600 may be located between the second electrode 200 and the n-typecharge generating layer.

The organic light emitting display may further include a chargegenerating layer 500 located between at least two organic light emittinglayers 300 and 400. The charge generating layer 500 may include ann-type charge generating layer and a p-type charge generating layer.

The p-type charge generating layer may generate holes and electrons. Thegenerated holes may be injected into the organic light emitting layer400 adjacent on, e.g., to, the upper side, and the generated electronsmay be injected into the n-type charge generating layer and theninjected into the organic light emitting layer 300 adjacent on, e.g.,to, the lower side.

The n-type charge generating layer may inject the electrons generatedfrom the p-type charge generating layer into the organic light emittinglayer 300 on the lower side. The n-type charge generating layer may bemade of the same material as that of an electron transport layer, whichwill be described later.

FIG. 2 illustrates a cross-sectional view of an organic light emittingdisplay according to an embodiment. As shown in FIG. 2, the chargegenerating layer 500 may include an n-type charge generating layer 510and a p-type charge generating layer 520, which are separated from eachother. The n-type charge generating layer 510 may be located adjacent tothe first electrode 100, e.g., relative to the p-type charge generatinglayer 520, and the p-type charge generating layer 520 may be locatedadjacent to the second electrode 200, e.g., relative to the n-typecharge generating layer 510. The n-type charge generating layer 510 maybe formed in contact with the organic light emitting layer 300 locatedon the lower side, and the p-type charge generating layer 520 may beformed in contact with the organic light emitting layer 400 located onthe upper side. The n-type charge generating layer 510 and the p-typecharge generating layer 520 may be formed in contact with each other.

The other configurations may be the same as described above, and a moredetailed description will be omitted.

FIGS. 3 and 4 illustrate cross-sectional views of an organic lightemitting display according to an embodiment. In the organic lightemitting display of FIGS. 3 and 4, the quantum dot materials may beremoved from the organic light emitting display of FIGS. 1 and 2. Asshown in FIGS. 3 and 4, the quantum dot materials may not be included inthe color filters 910 and 950.

The other configurations may be the same as described above, and arepeated description will be omitted.

FIG. 5 illustrates a cross-sectional view of an organic light emittingdisplay according to an embodiment. Referring to FIG. 5, color filters911 and 951 may include first regions 915 and 955 adjacent to the secondelectrode 200, and second regions 925 and 965. For example, the colorfilter 911 (951) may include the first region 915 (955) and the secondregion 925 (965), which are separated from each other. The secondregions 925 and 965 may be formed adjacent to the sealing substrate 700,or in contact with the sealing substrate 700.

The first color filter 911 may be divided into the first region 915 andthe second region 925, and the second color filter 951 may be dividedinto the first region 955 and the second region 965.

The quantum dot materials 10 and 20 may be located only in the secondregions 925 and 965. For example, the quantum dot materials 10 and 20may be formed at positions, adjacent to the sealing substrate 700, inthe respective color filters 911 and 951 to help increase colorconversion efficiency. By forming the quantum dot materials 10 and 20 tobe close to the sealing substrate 700, it may be possible to prevent themixing of colors between the second color light L2 and the third colorlight L3, and high-purity colors may be implemented.

In an embodiment, the quantum dot materials 10 and 20 may be locatedinside the color filters and may have a constant concentration gradient.The concentration gradient may be set such that the quantum dotmaterials have a higher concentration as they are closer to the sealingsubstrate.

FIG. 6 illustrates a cross-sectional view of an organic light emittingdisplay according to an embodiment.

Referring to FIG. 6, the organic light emitting display may include afirst charge transfer region 830 and 840 located between the firstelectrode 100 and the organic light emitting layer 300 and a secondcharge transfer region 810 and 820 located between the second electrode200 and the organic light emitting layer 400. Any one of the firstcharge transfer region 830 and 840 and the second charge transfer region810 and 820 may be responsible for the transfer of holes, and the otherone thereof may be responsible for the transfer of electrons.

In this embodiment, the first electrode 100 may be an anode electrodeand the second electrode 200 may be a cathode electrode. The firstcharge transfer region 830 and 840 adjacent to the anode electrode maybe a hole transfer region, and the second charge transfer region 810 and820 adjacent to the cathode electrode may be an electron transferregion.

The first charge transfer region 830 and 840 may have a single layerstructure made of a single material or different materials, or amultilayer structure including plural layers made of differentmaterials. In an embodiment, the first charge transfer region 830 and840 may further include a buffer layer and a first charge blockinglayer. In an embodiment, any one of the hole injection layer 830 and thehole transport layer 840 may be omitted, or the hole injection layer 830and the hole transport layer 840 may be configured as a single layer.

The hole injection layer 830 may be disposed on the first electrode 100,and may increase the efficiency of hole injection into the organic lightemitting layers 300 and 400 from the first electrode 100. For example,the hole injection layer 830 may decrease an energy barrier, and mayallow the holes to be injected efficiently.

The hole injection layer 830 may include, for example, a phthalocyaninecompound such as copper phthalocyanine (CuPc),m-MTDATA(4,4′,4″-tris(N-3-methylphenyl-N-phenylamino)triphenylamine),TDATA(4,4′,4″-tris(diphenylamino)triphenylamine),2-TNATA(4,4′,4″-tris[2-naphthyl(phenyl)-amino]triphenyl-amine),Pani/DBSA(Polyaniline/Dodecylbenzenesulfonic acid),PEDOT/PSS(Poly(3,4-ethylene dioxythiophene)/Polystyrene sulfonate),PANI/CSA (Polyaniline/Camphorsulfonic acid), or PANI/PSS(Polyaniline/Polystyrene sulfonate).

The hole transport layer 840 may be disposed on the hole injection layer830 and may transport the holes injected into the hole injection layer830 to the organic light emitting layers 300 and 400. When the highestoccupied molecular energy (HOMO) of the hole transport layer 840 issubstantially lower than the work function of a material forming thefirst electrode 100, and is substantially higher than the HOMO of theorganic light emitting layers 300 and 400, the hole transport efficiencymay be optimized. The hole transport layer 840 may include, for example,NPD(4,4′-bis[N-(1-napthyl)-N-phenyl-amino]biphenyl),TPD(N,N′-diphenyl-N,N′-bis[3-methylphenyl]-1,1′-biphenyl-4,4′-diamine),s-TAD(2,2′,7,7′-tetrakis-(N,N-diphenylamino)-9,9′-spirobifluoren), orm-MTDATA(4,4′,4″-tris(N-3-methylphenyl-N-phenylamino)triphenylamine).

The first charge transfer region 830 and 840 may further include acharge generating material to improve conductivity in addition to theabove-mentioned materials. The charge generating material may bedistributed uniformly or non-uniformly in the first charge transferregion 830 and 840. The charge generating material may be, for example,a p-dopant. The p-dopant may be, for example, one of a quinonederivative, metal oxide and a cyano group-containing compound. Examplesof the p-dopant may include a quinone derivative such asTCNQ(Tetracyanoquinodimethane) and TCNQ(Tetracyanoquinodimethane), andmetal oxide such as tungsten oxide and molybdenum oxide.

As described above, the first charge transfer region 830 and 840 mayfurther include at least one of the buffer layer and the first chargeblocking layer. The buffer layer may increase the light emissionefficiency by compensating for a resonance distance according to thewavelength of light emitted from the organic light emitting layers 300and 400. As a material included in the buffer layer, a material that maybe included in the first charge transfer region 830 and 840 may be used.The first charge blocking layer may prevent the injection of chargesinto the first charge transfer region 830 and 840 from the second chargetransfer region 810 and 820.

The organic light emitting layers 300 and 400 may be disposed on thefirst charge transfer region 830 and 840. The organic light emittinglayers 300 and 400 may be made of a material that may be used for lightemitting layers. For example, the organic light emitting layers 300 and400 may be made of materials emitting red, green and blue light. In anembodiment, the organic light emitting layers 300 and 400 may be made ofa material emitting blue light. The organic light emitting layers 300and 400 may include a fluorescent material or phosphorescent material.

In an exemplary embodiment, the organic light emitting layers 300 and400 may include a host and a dopant.

As the host, for example, Alq3(tris-(8-hydroyquinolato) aluminum(III)),CBP(4,4′-N,N′-dicarbazole-biphenyl), PVK(poly(N-vinylcarbazole)),ADN(9,10-Bis(2-naphthalenyl)anthracene),TCTA(4,4′,4″-tris(Ncarbazolyl)triphenylamine),TPBi(1,3,5-tris(N-phenylbenzimiazole-2-yl)benzene), TBADN(2-(t-butyl)-9,10-bis (20-naphthyl) anthracene), DSA(distyrylarylene),CDBP(4,4′-Bis(9-carbazolyl)-2,2′-Dimethyl-biphenyl), orMADN(2-Methyl-9,10-bis(naphthalen-2-yl)anthracene) may be used.

As the dopant, both a fluorescent dopant and a phosphorescent dopant maybe used. The kind of the dopant may vary according to the light emissioncolor of the organic light emitting layers 300 and 400.

As the red dopant, for example, a fluorescent material includingPBD:Eu(DBM)3(Phen)(2-biphenyl-4-yl-5-(4-t-butylphenyl)-1,3,4-oxadiazole:Tris(dibenzoylmethane)mono(1,10-phenanthroline)europium(111)) or perylene may be used. In anembodiment, a phosphorescent material including a metal complex such asPIQIr(acac)(bis(1-phenylisoquinoline)acetylacetonate iridium),PQIr(acac)(bis(1-phenylquinoline)acetylacetonate iridium),PQIr(tris(1-phenylquinoline)iridium) and PtOEP(octaethylporphyrinplatinum) or an organometallic complex may be used.

As the green dopant, for example, a fluorescent material includingAlq3(tris-(8-hydroyquinolato) aluminum(III)) may be used. In anembodiment, a phosphorescent material including, for example,Ir(ppy)3(fac tris(2-phenylpyridine)iridium),Ir(ppy)2(acac)(Bis(2-phenylpyridine)(acetylacetonate)iridium(III)), orIr(mpyp)3(2-phenyl-4-methyl-pyridine iridium), may be used.

As the blue dopant, for example, a fluorescent material including one ofspiro-DPVBi(spiro-4,′-bis(2,2′-diphenylvinyl)1,1′-biphenyl),spiro-6P(spiro-sixphenyl), DSB(distyrylbenzene), DSA(distyrylarylene),PFO(polyfluorene)-based polymer and PPV(poly p-phenylenevinylene))-based polymer may be used. In an embodiment, a phosphorescentmaterial including, for example,F2Irpic(bis[2-(4,6-difluorophenyl)pyridinato-N,C2′]iridium picolinate),(F2ppy)2Ir(tmd)(bis[2-(4,6-difluorophenyl)pyridinato-N,C2′]iridium2,2,6,6-tetramethylheptane-3,5-dione), orIr(dfppz)3(tris[1-4,6-difluorophenyl)pyrazolate-N,C2′]iridium), may beused.

The second charge transfer region 810 and 820 may be disposed on theorganic light emitting layers 300 and 400. The second charge transferregion 810 and 820 may have a single layer structure made of a singlematerial or different materials, or a multilayer structure includingplural layers made of different materials. In an embodiment, the secondcharge transfer region 810 and 820 may further include a second chargeblocking layer. As illustrated in the figure, the second charge transferregion 810 and 820 may include an electron transport layer 820 and anelectron injection layer 810. In an embodiment, any one of the electrontransport layer 820 and the electron injection layer 810 may be omitted,or the electron transport layer 820 and the electron injection layer 810may be configured as a single layer.

The electron transport layer 820 may be disposed on the organic lightemitting layers 300 and 400, and may transport electrons injected fromthe electron injection layer 810 toward the organic light emittinglayers 300 and 400.

The electron transport layer 820 may include, for example,Alq3(tris-(8-hydroyquinolato) aluminum(III)),TPBi(1,3,5-tris(N-phenylbenzimiazole-2-yl)benzene),BCP(2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline),Bphen(4,7-diphenyl-1,10-phenanthroline),TAZ(3-(Biphenyl-4-yl)-5-(4-tert-butylphenyl)-4-phenyl-4H-1,2,4-triazole),NTAZ(4-(naphthalen-1-yl)-3,5-diphenyl-4H-1,2,4-triazole),tBu-PBD(2-(4-biphenylyl)-5-(4-tert-butyl-phenyl)-1,3,4-oxadiazole),BAlq(Bis(2-methyl-8-quinolinolato-N1,O8)-(1,1′-Biphenyl-4-olato)aluminum),Bebq2(Bis(10-hydroxybenzo[h]quinolinato)beryllium),ADN(9,10-bis(2-naphthyl)anthracene) or a mixture thereof.

The electron injection layer 810 may be disposed on the electrontransport layer 820, and may increase the efficiency of electroninjection into the organic light emitting layers 300 and 400 from thesecond electrode 200.

As the electron injection layer 810, for example, lanthanide metal suchas LiF, LiQ (lithium quinolrate), Li2O, BaO, NaCl, CsF and Yb, or halidemetal such as RbCl and RbI may be used. The electron injection layer 810may also be made of a mixture of the above-mentioned material and organometal salt that may have an insulating property. The organo metal saltmay be a material that may have an energy band gap of about 4 eV ormore. For example, the organo metal salt may include metal acetate,metal benzoate, metal acetoacetate, metal acetylacetonate or metalstearate.

As mentioned above, the second charge transfer region 810 and 820 mayfurther include the second charge blocking layer. The second chargeblocking layer may include one or more of, for example,BCP(2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline) orBphen(4,7-diphenyl-1,10-phenanthroline).

Provided is a manufacturing method of an organic light emitting display.Hereinafter, a manufacturing method of an organic light emitting displaywill be described with reference again to FIGS. 1 to 6.

The manufacturing method of an organic light emitting display mayinclude forming the first electrode 100 above the substrate 50, formingat least two organic light emitting layers 300 and 400 above the firstelectrode 100 while the charge generating layer 500 is interposedbetween the organic light emitting layers 300 and 400, and forming thesecond electrode 200 above the organic light emitting layers 300 and400.

The organic light emitting layers may be formed using a solublematerial. For example, the organic light emitting layers may be formedusing a material containing a solvent. The organic light emitting layersmay be formed by mixing a material forming the organic light emittinglayers with a solvent, coating the mixed material and solvent by anink-jet printing method or a discharging method using a slit nozzle, andthen, performing a drying and baking step. Thus, it may be possible tosimplify a manufacturing process, and it may be possible to reduce theunit price of the product by reducing the manufacturing cost. By formingat least two organic light emitting layers, it may be possible toincrease the luminous efficiency.

The formation of the organic light emitting layers may be performedunder conditions of normal pressure. For example, the formation of theorganic light emitting layers may be performed under conditions ofatmospheric pressure, or about 1 atmosphere. Since the formation of theorganic light emitting layers may be performed under conditions ofatmospheric pressure, it may not separately require conditions of vacuumor reduced pressure. Thus, it may be possible to manufacture the organiclight emitting display without using an expensive manufacturingapparatus, and the unit price of the product may be reduced. Inexamples, other organic/inorganic layers in addition to the organiclight emitting layers may be formed under conditions of normal pressure.Therefore, the overall manufacturing process of the organic lightemitting display may be performed under conditions of normal pressure,and there may be an advantage of reducing the manufacturing cost whilesimplifying the manufacturing process. In an embodiment, the formationof the second electrode may be performed under conditions of reducedpressure or vacuum by a sputtering process.

The manufacturing method of an organic light emitting display mayfurther include forming at least one of a hole injection layer and ahole transport layer between the first electrode and the organic lightemitting layers to supply holes generated from the first electrode tothe organic light emitting layers, and forming at least one of anelectron injection layer and an electron transport layer between thesecond electrode and the organic light emitting layers to supplyelectrons generated from the second electrode to the organic lightemitting layers. The hole transport layer, the hole injection layer, theelectron transport layer and the electron injection layer have beenalready described in conjunction with the organic light emittingdisplay, and a more detailed description will be omitted.

The manufacturing method of an organic light emitting display mayfurther include forming a buffer layer including one or more of WO₃,MoO_(x), or HATCN below the second electrode. The second electrode maybe formed using the above-mentioned materials forming the secondelectrode by a sputtering method. The organic layers located between thefirst electrode and the second electrode may be damaged. By forming thebuffer layer, in a process of forming the second electrode, it may bepossible to prevent damage or performance degradation of various organiclayers located between the first electrode and the second electrode, forexample, due to the material forming the second electrode.

The manufacturing method of an organic light emitting display mayfurther include preparing a sealing substrate on which at least twocolor filters including quantum dot materials are formed, and laminatingthe substrate and the sealing substrate while the color filters arelocated to face, e.g., be separated from, the second electrode. Thequantum dot materials, the color filters, and the sealing substrate, forexample, have been already described, and a redundant description willbe omitted.

By way of summation and review, an organic light emitting display may bea self-luminous type display for displaying an image by using an organiclight emitting diode that emits light. The organic light emittingdisplay may be configured such that holes and electrons are injected bya first electrode and a second electrode, the injected holes andelectrons are coupled in a light emitting layer located between thefirst electrode and the second electrode, and light may be generated byenergy generated when exitons formed by the coupling fall to the groundstate.

The organic light emitting diode may include, for example, a holeinjection layer, a hole transport layer, an electron injection layer,and an electron transport layer, in addition to an organic lightemitting layer between an anode and a cathode.

An organic light emitting diode that emits white light may be referredto as a white organic light emitting diode.

According to embodiments, it may be possible to provide an organic lightemitting display that may be capable of improving color purity whilepreventing a change in color according to a viewing angle.

Also, it may be possible to provide a manufacturing method of an organiclight emitting display, that may be capable of facilitating themanufacture and reducing the manufacturing cost.

Example embodiments have been disclosed herein, and although specificterms are employed, they are used and are to be interpreted in a genericand descriptive sense only and not for purpose of limitation. In someinstances, as would be apparent to one of skill in the art as of thefiling of the present application, features, characteristics, and/orelements described in connection with a particular embodiment may beused singly or in combination with features, characteristics, and/orelements described in connection with other embodiments unless otherwisespecifically indicated. Accordingly, it will be understood by those ofskill in the art that various changes in form and details may be madewithout departing from the spirit and scope of the present invention asset forth in the following claims.

What is claimed is:
 1. A display, comprising: a first substrate; a lightemitting device disposed on the first substrate; and a color conversionlayer disposed on the first substrate, the color conversion layeroverlapping the light emitting device and including a quantum dot,wherein the light emitting device includes, a first electrode disposedon the first substrate, a first light emitting layer disposed on thefirst electrode, a second light emitting layer disposed on the firstlight emitting layer, and a second electrode disposed on the secondlight emitting layer, wherein the light emitting device further includesan electron injection layer between the second electrode and the secondlight emitting layer, wherein the electron injection layer includes oneor more of LiF, LiQ (lithium quinolate), Li₂O, BaO, NaCl, CsF, Yb, RbCl,or RbI, wherein the first light emitting layer and the second lightemitting layer emit a same color light, and wherein the color conversionlayer is spaced apart from the first electrode and the second electrode.2. The display as claimed in claim 1, wherein both of the first lightemitting layer and the second light emitting layer emit a blue colorlight.
 3. The display as claimed in claim 2, wherein the light emittingdevice further includes a charge generating layer between the firstlight emitting layer and the second light emitting layer.
 4. The displayas claimed in claim 3, wherein the charge generating layer includes ann-type charge generating layer and a p-type charge generating layer. 5.The display as claimed in claim 1, further comprising a second substratefacing the first substrate, wherein the color conversion layer isdisposed between the second substrate and the second electrode.
 6. Thedisplay as claimed in claim 1, wherein the color conversion layerincludes a first color conversion pattern including a first quantum dotand a second color conversion pattern including a second quantum dot,and wherein a size of the first quantum dot is different from the secondquantum dot.
 7. A display, comprising: a substrate; a first electrodedisposed on the substrate; a second electrode facing the firstelectrode; at least two light emitting layers between the firstelectrode and the second electrode, the at least two light emittinglayers overlapping each other; and a color conversion layer disposed onthe substrate, the color conversion layer including a quantum dotmaterial and overlapping the at least two light emitting layers, whereinthe display further comprises a buffer layer between the secondelectrode and the at least two light emitting layers, and wherein thecolor conversion layer is spaced apart from the first electrode and thesecond electrode.
 8. The display as claimed in claim 7, wherein thebuffer layer is an oxide layer.
 9. The display as claimed in claim 7,wherein the at least two light emitting layers each emit a same colorlight.
 10. The display as claimed in claim 7, further comprising anelectron injection layer between the second electrode and the at leasttwo light emitting layers, wherein the electron injection layer includesone or more of LiF, LiQ (lithium quinolate), Li₂O, BaO, NaCl, CsF, Yb,RbCl, or RbI.